Tectonic Hazards Flashcards
What are plate margins?
Plate margins are where tectonic plates meet and rub against one another.
What are oceanic plates?
Oceanic plates are found beneath the ocean and are the thinner plates, between 5-10 km thick. They are typically younger than continental plates, as new plate material is still made at plate boundaries.
What are continental plates?
Continental plates are found carrying land, and are far thicker, usually being between 35-100 km thick.
What are convection currents?
Convection currents waves of rising heat from the mantle that move the plates towards and away from each other.
What are constructive plate margins?
Constructive plate margins are where the plates move apart, often under the sea. This causes magma to erupt from the surface of the Earth, which then cools to form igneous rock. This process is accompanied by earthquakes and can form volcanoes.
What are destructive plate margins?
When a continental plate and an oceanic plate move towards each other, the denser oceanic plate is pushed beneath the continental plate. The oceanic plate is melted within the subduction zone into magma, which collects into a magma chamber and rises through the cracks of the continental plate. This can cause Earthquakes and volcanic activity.
What are collision plate margins?
When two oceanic plates move towards each other, the layers of sedimentary rock crumple and fold together, eventually appearing above sea level as a range of fold mountains. This may cause earthquakes and volcanoes.
What are conservative plate margins?
When two plates move past each other along fault lines they can become caught and build up friction and energy which is released as an earthquake.
What are the layers of the Earth?
Crust: The outmost layer of the Earth, and the thinnest between 5-70 km thick. It is a solid rock layer.
Mantle: The thickest layer of the Earth, with approximately of 2,900 km. It is made up of magma, which gets harder closer to the crust.
The outer core: The layer surrounding the inner core, made entirely of liquid iron and nickel .
The inner core: The centre of the Earth is made of solid iron and nickel, with temperatures of around 5,500*C
